An Awkward Little Crypt
Made of Debris from Previous Centuries

This is a very small space: you're looking at about two-thirds of it. One of its unusual features is that there are three supporting columns, not four. We don't have a mini-nave with side aisles at all; we have some serious structural support going on here. I still wonder why not four, though. (The layout is made even clearer by
this view
of the crypt taken in the opposite direction, from behind the altar towards the exit to ground level.)

Other than sheer atmosphere, the most intriguing feature of this dark hole — which rates a star from the normally sober
Touring Club Italiano guide to Umbria
— is the reuse of ancient, almost certainly Roman materials.

No high art here, though. Let's bring forward the column you see above right next to the altar, and look carefully at the "capital". The antique column has in fact been turned upside down, and it is from a column base that the vaults are made to spring; this isn't uncommon in very old churches, but that star still puzzles me.

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